Evaluate Restoration Potential of Snake River Fall Chinook Salmon Spawning Habitat

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Evaluate Restoration Potential of Snake River
Fall Chinook Salmon Spawning Habitat

• Project 35007
• Tim Hanrahan
• Pacific Northwest National Laboratory
• Richland, WA

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Background

• Battelle and USGS. 2000. Assessment of the
  impacts of development and operation of the
  Columbia River hydroelectric system on mainstem
  riverine processes and habitats. BPA Final
  Report DOE/BP-08104-1.
• Less than 20 of historic production areas still
  available
• Greatest restoration potential Little
  Goose/Lower Granite, Columbia/Snake/Yakima areas,
  John Day

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Swan Falls Reach
Hells Canyon Reach
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Mainstem Habitat Restoration Opportunities
only by increasing the amount of riverine
habitat available for spawning and rearing via
operational changes of selected hydroelectric
projects.
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Research Goals

• Identify segments, within the hydrosystem, where
  potentially suitable fall chinook spawning
  habitat exists.
• Determine adjustments in hydrosystem operations
  that would be necessary for these segments to
  function as spawning areas.

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Rationale and Significance to Regional Programs

• RPA 155 in NMFS 2000 Biological Opinion on FCRPS
• Investigate restoration potential of subyearling
  migratory and fall chinook spawning habitat
  before 3 yr. implementation check in 2003. (BiOp
  Gap Analysis)
• Identify mainstem habitat sampling reaches,
  survey conditions, describe cause-effect,
  identify research needs
• Develop improvement plans for mainstem reaches
• Initiate improvements in three mainstem reaches

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Rationale . . . , contd

• NPPC 2000 Fish and Wildlife Program
• Emphasizes a habitat-based approach to restoring
  fish populations, including adjusting mainstem
  hydrosystem operations (Section III.A.2)
• Calls for restoring mainstem spawning and rearing
  areas adjacent to historically- and
  currently-productive areas, as well as in areas
  likely to sustain healthy populations (Sections
  III.D.3 and III.D.6.f)
• Draft Subbasin Summaries
• Restore mainstem salmonid habitats

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Threatened species and targeted stocks

• Fall chinook salmon (Oncorhynchus tshawytscha)
• Snake River fall-run ESU, listed as Threatened
  under ESA on 22 April 1992
• Upper Columbia River fall-run ESU, expansion of
  healthy Hanford Reach population

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Research Questions

• Where are the segments of potentially suitable
  fall chinook spawning habitat within each study
  area?
• What adjustments in hydrosystem operations are
  required for these segments to mimic existing
  spawning areas?

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Study Areas and Reference Sites

• Study Areas
• Lower section of the Hanford Reach
• Ice Harbor Dam tailrace to Columbia River
  confluence
• Lower Granite Dam tailrace
• Two types of riverine habitat
• upper reservoir
• tailwater
• Reference Sites
• Hanford Reach
• Wanapum Dam tailrace

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Study Areas
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Hanford Reach Reference Site5400 redds, 42000
adults (10yr avg), 73 rkm
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Wanapum Dam Tailrace Reference Site2100 redds,
9600 adults, 5 rkm
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Objectives and Approach

• Objective 1 Quantify the physical
  characteristics defining suitable fall chinook
  spawning habitat at the upper reservoir and
  tailwater reference sites
• Approach
• Map spawning areas
• Collect physical characteristic data
  (physiography, hydrologic regime, channel
  morphology, hydraulics, water quality)
• Setup 2D hydrodynamic model

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Objectives and Approach

• Objective 2 Quantify the physical
  characteristics at each of the study sites.
• Approach
• Collect physical characteristic data
  (physiography, hydrologic regime, channel
  morphology, hydraulics, water quality)
• Setup 2D hydrodynamic model

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Objectives and Approach

• Objective 3 Quantify the physical
  characteristics at the study sites under a range
  of flow conditions
• Approach
• Apply 2D model to varying operational scenarios
  (forebay/tailrace elevations) and water-year types

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Objectives and Approach

• Objective 4 Determine what changes in
  hydrosystem operations are required to cause
  physical characteristics at study sites to
  resemble those at reference sites.
• Approach
• Compare the results from Objectives (1) and (3)
  to determine the presence and extent of similar
  characteristics

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Expected Results

• Location and spatial extent of potential spawning
  habitat restoration areas for Threatened Snake
  River fall chinook ESU
• Recommendations for adjusting hydrosystem
  operations to improve fall chinook spawning
  habitat
• Alternative flow scenarios by water-year type